Are any of the items 220vac? You should not arbitrarily connect neutrals from different circuits. A GFCI shold not be installed downstream from another GFCI. First, it's not necessary assuming it is fed from the load side. You could install it on the line side, but then why since one would protect everything downstream anyway when wired to the load side.
Keep in mind that a white wire is not necessarily a neutral - it could be a switched hot wire.